Milk amount measuring device for milking machines and the method for measuring the same

ABSTRACT

A device which measures the amount of milk which has been milked by a combination of a swinging member 2 and a tank 5; and a weight balance section, thereby enhancing accuracy in measurement as well as reducing in size the device. A measuring method for total milk amount by using the measuring device and by measuring the amount of milk which is filled in the tank 5 and the amount of milk which does not flow into the tank 5 at the time of discharging with the rotational cycles of the swinging member 2 to thereby achieve a higher precision.

FIELD OF THE INVENTION

The present invention relates to a device for measuring the totalquantity milked by a machine and more particularly, to a milk measuringdevice for milking machines comprising a measuring means which repeatsrotating movements in the vertical direction corresponding to the flowrate of milk. The present invention further relates to a measuringmethod of total milk quantity which has been milked.

BACKGROUND OF THE INVENTION

FIG. 1 shows a prior art milk measuring device (U.S. Pat. No. 2,998,722)Within containers 12, 13 are housed a separating chamber 16 forseparating milk from the mixture of milk and air which has been milkedfrom a cow and a measuring means 14 which is positioned beneath theseparating chamber 16 and which repeats vertically revolving movementsin correspondence to the flow rate. The milk mixture extracted by amilking machine is guided into an inlet port 15 provided on the top ofthe container 12 via a milk tube (not shown) and then into theseparating chamber 16. The mixture of milk and air which has beendirected into the separating chamber 16 is reduced in inlet energy by arectifying plate 17 and the milk is directed to flow into the measuringmeans 14 through an outlet port 18 provided on the bottom of theseparating chamber 16. The air separated from the milk passes through anarrow space 20 provided between the container 12 and the chamber 16 toarrive at an outlet port 21 on the bottom of the container 13, rejoinsthe milk which has passed through the measuring means 14 and is finallyguided into a milk supply tube (not shown). The measuring device 14comprises two tanks to temporarily store the milk which are journaledrotatively on an axis 14a fixed on the container 13. The measuringdevice 14 further comprises permanent magnets 19a on the bottoms ofrespective tanks. Magnets 19b are provided on the container 13 tocorrespond to the magnets 19a. When milk flows and stands in a tank inan amount which sufficiently overcomes the magnetic attraction betweenthe magnet 19a of the other tank and the magnet 19b correspondingthereto, the weight equilibrium between two sides of the axis 14abreaks, to thereby lower the tank containing the milk around the axis14a to the extent where the magnet thereof is attracted and attached tothe other corresponding magnet. That makes the standing milk to flow outof the tank and meanwhile, the milk which is being milked continuouslyflows in to the other tank of the measuring means 14.

The total amount of milk can be measured by detecting the number ofmovements of the measuring means 14 which repeats the above mentionedmovements and multiplying the number by the amount of milk which is tobe discharged by one movement of the means 14.

The prior art device mentioned above, however, is detrimental in thefollowing aspects:

As the measuring means 14 is structured with two tanks and as theposition of the means 14 must be retained while milk is being filled inone of the tanks, the other tank must have a given retaining force whichcounter-balances the predetermined amount of milk in the first tank. Inorder to give such a retaining force, the suction of magnets isutilized. However, the magnetic force of magnets varies widely.Moreover, as the magnetic force changes suddenly in a mannercounter-proportionate to the square of distance, it is necessary tomount a special mechanism for adjusting the magnetic force on the deviceso as to cause a pair of magnets to generate a predetermined suctionforce, presenting difficulties in cost and size of the prior art device.

As the magnetic force of a magnet undergoes chronological changes byvarious factors, it is extremely difficult to maintain the predeterminedprecision thereof for a long term without proper maintenance service.Even with periodical maintenance service, it is still difficult forusers to adjust the device to the predetermined precision.

As the means 14 has two tanks, the size of the device per se becomesinevitably bulky presenting trouble in transportation while milking.

Another prior art measuring device as shown in FIGS. 11 and 12 has beenknown; wherein the filling time of milk into a measuring container andthe discharging time thereof are measured (JAP Laid-Open No. Sho57-18926). When a measuring chamber 55 is being filled with a valve 50closed, the time Ci required for a float 53 to move from the lowermagnetic sensor 51 to the upper magnetic sensor 52 is measured by theabove two sensors. Within that time period, the volume V is filled inthe chamber 55. After the float 53 has reached the sensor 52, a milkoutlet port 54 is opened via the valve 50 and the float 53 goes down tothe sensor 51 within the time di. Then, the valve 50 is closed and thefloat goes up again. Qi represents the average partial flow rate and isexpressed by the equation,

    Qi=(V/ci).

If it is assumed that the flow comes in within the time di at apredetermined average partial flow rate, the volume Vi which flows inwithin the time, bi=ci+di can be expressed as below;

    Vi=Qi×x bi=(bi/ci)×V

The total amount of the extracted milk which is measured by n times canbe obtained from the equation; ##EQU1##

The prior art measuring method, however, is defective in that, as it isassumed that the milk which flows in within the time required for theliquid level to move from the upper sensor 52 to the lower sensor 51supposedly flows at the average partial flow rate Qi of the filling timeci. In actual milking operation, the partial flow rate in the fillingtime does not necessarily coincide with the partial flow rate in thedischarging time and therefore, a high precision in measuring can not beexpected.

DISCLOSURE OF THE INVENTION

In order to obviate the aforementioned defects in prior art, thisinvention aims at providing a device for measuring milk for milkingmachines which is compact in size and simple in maintenance. The devicecomprises a swinging member 2 which comprises a balance member 3 havinga weight on one side and a milk tank 5 on the other side which is openat the upper portion, a shaft 1 which supports said swinging member 2 ina manner vertically rotatable, a stop means 8 provided near the swingingmember 2 to restrict the scope of rotational movement thereof, and asensor means 9 which detects the rotational cycles of said swingingmember 2.

As the measuring means has now only one tank instead of two tanks,maintenance operation is unnecessary for quite a long period of time andyet the desired precision can be maintained. This invention cantherefore provide a device smaller in size and lower in cost comparedwith prior art milk measuring device.

This invention also provides a measuring method for milk quantity inorder to improve the measuring precision. In the measuring method whichmeasures the total milk amount wherein extracted milk flows in andstands in a tank temporarily for a certain period of time and then flowsout, and this operation is repeated consecutively, the measuring methodcomprises the steps of measuring partial milk amounts Yi (g/cycle) whichcorresponds to respective cycles Ti from the beginning of filling untilthe completion of discharge and preparing a partial milk amount cyclecurve, measuring respective cycles of filling and discharging of milk inor out of the tank from the beginning till the end of the milkingoperation, and obtaining the sum of partial milk amounts correspondingto each cycle. The method according to this invention also comprisessteps of measuring two average partial flow rates q_(i) and q_(i+1) eachat two different time points in filling cycles immediately before andafter the discharge, measuring a filling time t_(i) and a dischargingtime s_(i), and calculating the total sum of the products of thearithmetric mean partial flow rate r_(i) ##EQU2## and the total sum ofthe products of the average partial flow rate of the filling cycle t_(i)and the filling time t_(i), that is, Σ(r_(i) ×s_(i) +q_(i) ×t_(i)).

In the former method, instead of calculating the amount of milk fromassumption, the milk amount can be obtained with minimized error as thepartial milk amounts corresponding to each cycle from the beginning offilling until the completion of discharge have been actually measured.In the latter method, measurement with a higher precision can beperformed as the average partial flow rate is calculated by averagingthe flow rates at two time points in the filling period both before andafter the discharge so as to deal with rapid and drastic changes in flowrate during milking operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of a prior art milk measuring device.

FIGS. 2 through 6 show the first embodiment wherein FIG. 2 is a crosssection and FIGS. 3 and 4 detailed views of a bearing member of aswinging member.

FIGS. 7 through 10 show the second embodiment of the measuring deviceaccording to this invention;

FIG. 7 a cross section,

FIGS. 8 and 9 cross sections along the line X--X of FIG. 7, and

FIG. 10 a perspective view of another embodiment of the measuring means.

FIGS. 11 and 12 concern a conventional method for measuring the milkamount;

FIG. 11 is a cross section of a milk measuring device and

FIG. 12 a graph to show the relation between the height of liquid leveland the time.

FIGS. 13 and 15 relate to the first measuring method according to thisinvention;

FIG. 13 is a graph of lactating curve of cows in general,

FIG. 14 a diagram of signals of the sensor means and the cycle T, and

FIG. 15 a y - T characteristic curve graph in the measuring device shownin FIG. 7.

FIGS. 16 and 17 relate to the second measuring method;

FIG. 16 shows a lactating curve of cows in general while

FIG. 17 is a diagram of the relation between the signals and thefilling/discharging time of the sensor means.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described referring to preferredembodiments shown in FIGS. 2 through 10 and FIGS. 13 through 17respectively.

In the drawings, the reference numeral 16 denotes a separating chamberfor separating the mixture of milk and air. The separating chamber 16comprises a container 12 having an inlet port 15 for milk and an outletport 18 on the bottom and a lid 23 to be capped over the container 12.The reference numeral 35 denotes a strainer to remove impurities such asdust from the milk. A container 13 having an outlet port 21 is mountedbelow the container 12 in a detachable manner. The container 12 iscommunicated with a measuring chamber 22 by an air pipe 12b whichprojects upwardly from the bottom of the container 12. The measuringchamber 22 has a swinging member 2 which is suspended from the lowerportion of the container 12 and which is freely rotatable around a shaft1 in the vertical direction. The swinging member 2 comprises a balancesection 3 comprising a weight on one side and a milk tank 5 which isopen on the upper portion thereof. The reference numeral 8a denotes aprojecting piece on the container 12 and 8b an abutting member of anelastic material such as rubber which is mounted in a detachable manneron the projecting piece 8a and is structured to abut against theswinging member 2 at a predetermined position in revolution thereof soas to function as a stop means restricting the scope of revolution. Thereference numeral 11 denotes a permanent magnet for actuating a reedswitch 10 provided on a container 13 so that a resilient member 8b comesto position close to the magnet 11 when it abuts against the swingingmember 2. The magnet 11 and the reed switch 10 constitute a sensor means9. The reference numeral 24 denotes a rectifying piece mounted in anoutlet port 21 to transform the milk current in the state of mass out ofa milk tank 5 into a continuous flow, thereby preventing fluctuation inmilking pressure. The reference numeral 25 denotes a computer/displaywhich converts the signals from the sensor means 9 into the figuresrepresenting the amount of milk and display them.

FIGS. 3 and 4 show a swinging member 2 in more detail. A shaft 1 isinserted into the swinging member 2 via an O-ring 1_(a) made of aresilient material such as rubber. The reference numeral 30 denotesblocks of extremely light weight inserted in a plural number into a hole36 provided on the balancing section. The reference numeral 31 denotes abolt to press the blocks 30 and 32 another bolt to close the hole.

FIGS. 5 and 6 show the bearings of the swinging member 2 in detail. Theshaft 1 engages with a bearing 33 which is detachably engaged with amounting frame 34 suspended from the container 12.

The embodiment of the measuring device mentioned above is operated asbelow.

The milk extracted by a milking machine flows into a separating chamber16 from an inlet port 15 via a milk tube (not shown). The air contentwhich has been separated in the separating chamber 16 is guided into ameasuring chamber 22 via an air pipe 12b. The milk separated from theair, on the other hand, flows into and stands in a tank 5 via an outletport 18. As the milk gradually is accumulated to the extent where theamount of standing milk overcomes the weight of the balance section 3,the balance section 3 rotates upward to discharge the milk. Due to therevolution of the swinging member 2, the milk flowing out of the outletport 18 is guided downward into the bottom of the measuring chamber 22directly instead of passing through the tank 5. When the milk iscompletely discharged from the tank 5, the balance section 3 is made torotate downward by the weight thereof to make the resilient member 8babut against an end of the swinging member 2 so that milk begins toaccumulate in the tank 5 again. Since the quantity of milk which isdischarged from the tank 5 and the weight of the balance section 3 arerespectively constant, the fluctuation in individual rotations becomesnegligible to make the rotation almost constant timewise. The milk,after discharging from the tank 5, is reunited with the air which hasbeen separated, is rectified with a rectifying piece 24, and guided intothe milk tube (not shown) via an outlet port 21. The sensor means 9detects a rotating cycle of the swinging member 2 or the cycle from thetime when milk starts filling in the tank till the next start. Thepartial milk amounts from the outlet port 18 corresponding to respectiverotation cycles are calculated in advance as characteristics and thecomputer/display 25 obtains and displays the partial milk amount whichfits the cycle of rotation stored, and obtains the total amount of milkby summing the partial amounts.

According to the first embodiment of this invention, as mentioned above,the measuring device 14 does not require a retaining means (suction of amagnet) which used to be needed in the prior art two-tank structure toretain the position of the device 14 at the time when milk is beingfilled in a tank. The present invention device enhances the reliabilityin measurement easily by providing a simple weight without complicatedadjustment mechanism. As a plural number of light weight blocks areprovided on said balance section, even if the balance is slightlyfluctuated due to chronological changes in the bearings and/or theswinging member, that will be adjusted easily by changing the number ofblocks.

In the above embodiment the stop means 8 comprises a projection piece 8asuspended from the container 12 and a resilient member 8b. Although theshaft 1 may be formed to double as a stop means, the structure in such acase becomes extremely complicated and as the force applied thereon whenthe means works as a stop is large, it may be easily broken; therefore,the stop means is preferably positioned at a location apart from theshaft 1.

As the resilient member 8b is mounted on the abutting portion of thestop means in a freely detachable manner, the wear and tear of theportion which abuts against the stop means of the swinging member isreduced, thereby conveniently decreasing the fluctuation in balance ofthe swinging member per se. It is preferable to make the swinging memberto have less fluctuation in weight or, in other words, to have apredetermined constant ratio in moments of either sides of therotational shaft. For instance, plastic molding is preferable. Thematerial thereof is preferable to be superior in abrasion resistance aswell as to withstand impulsive loads. The material for the shaft ispreferably metals or ceramics. In order to couple the plastic main bodywith the rotational shaft of different materials, the methods such asultrasonic insert or insert at the time of molding may be used, but asthe stress is produced by the difference in thermal expansioncoefficients, they are not very desirable for the long term use. If ametal is used as the material for the sensor, it may be welded incoupling but when slight and delicate fluctuation in weight presents acritical problem, that would not be suitable. Therefore, in thisembodiment, a shaft having a high abrasion resistance is inserted in ahole bored in a plastic main body (the swinging member) via an O-shapedring which is made of a resilient material such as rubber.

As the shaft is inserted into the swinging member via the O-ring, theimpact during the rotation is alleviated and is not directly transferredto the shaft, the bearing portion thereof can be protected fromabrasion. The plastic main body (the swinging member) is also protectedfrom failures which might be otherwise caused by the difference inthermal expansion coefficients.

Although the sensor means 9 above is constituted with a reed switch 10and a permanent magnet 11 so as to actuate the reed switch 10 with themagnetic force, the structure thereof is not limited thereto. Anystructure is possible so far as it can generate signals at apredetermined position on the swinging member 2 to measure therotational cycle. As shown in FIGS. 5 and 6, since the bearing whichengages with the shaft is freely detachable in this embodiment, itbecomes easy to replace bearings when they are worn by the rotation ofthe member, thereby enabling maintenance of the original performance.

The material of the swinging member is preferably harder than that ofbearings so that abrasion between the shaft and the bearings may occurmainly on the side of the bearings.

The second embodiment according to this invention will now be explainedreferring to FIGS. 7 through 10. Description for the containers 12, 13will be omitted as they are identical to the ones explained for thefirst embodiment and a swinging member 2 made of a hollow member and astop means 8 will be explained below.

In a measuring chamber 22, a swinging member 2 of a hollow structure isvertically rotational around the axially extending shaft 1 which islocated in the lower portion of the container 13 and which functions asa fulcrum. Said swinging member 2 is partitioned on both sides of theshaft 1 into a balance section 3 comprising a weight and a milk tank 5having an outlet port 4. On the upper portion of the peripheral wall ofthe hollow swinging member 2 is provided a milk passage 7 which has afilling port 6 projected upward from the shaft 1 to let milk in andwhich leads to the tank 5. The reference numeral 8a denotes a projectionpiece provided on the container 13 which is so structured to abut on anend portion of the balance section 3 at a predetermined rotationalposition and constitutes a stop means 8 to define the rotational scopeof the member 2. When the projection piece 8a abuts against the balancesection 3, the filling port 6 is positioned to come directly under theoutlet port 18. The reference numeral 11 denotes a permanent magnetwhich actuates a reed switch 10 provided on the container 13 so as toposition the projection piece 8a close to the magnet 11 when it abutsagainst the balance section 3. The magnet 11 and the reed switch 10constitute a sensor means 9.

The second embodiment according to this invention having the abovementioned structure is operated as follows.

The milk extracted by a milking machine flows into a separating chamber16 from an inlet port 15 via a milk tube (not shown) The air contentseparated in the separating chamber 16 is guided to a measuring chamber22 through an air pipe 12b. The milk after being separated from the air,on the other hand, flows into the outlet port 18 to stand in the tank 5.When the standing milk increases and reaches a certain quantity toovercome the weight of the balance section 3, the section 3 rotatesupward to discharge the milk from the tank 5. The rotation of theswinging member 2 then causes the milk to drop directly onto the bottomof the measuring chamber 22 rather than passing through the tank 5. Whenthe milk has been discharged from the tank 5, the balance section 3 isrotated downward with the weight thereof and the projection piece 8acomes to abut against an end of the balance section to thereby let themilk accumulate again in the tank 5. As the amount of milk dischargingfrom the tank 5 and the weight of the balance section 3 are respectivelyconstant, the fluctuation in the time needed for individual rotations ofthe swinging member 2 is negligible and the time can be regarded almostconstant. The milk discharged from the tank 5 is reunited with the air,rectified by the rectifying piece 24, and guided into a milk tube forsupply (not shown) from the outlet port 21. The sensor means 9 measuresthe rotational cycle of the swinging member 2 or in other words, thecycle from the time starting the milk filling until the next start.Partial milk amounts from the outlet port 18 corresponding to respectiverotational cycles are obtained in advance as characteristics, partialmilk amount corresponding to measured rotational cycle is obtained fromthe stored characteristic and displayed by a computer/display 25, andthe sum of the partial amounts is calculated as the total milk amount.

As described above, in the second embodiment according to thisinvention, a swinging member 2 of a hollow structure is provided on theaxis or the shaft 1 in a manner vertically rotatable and is divided oneither side of the shaft into a balance section 3 having a weight and amilk tank 5 having an outlet port 4. Due to such a structure, the devicedoes not require a special means for retaining the swinging memberduring filling of the milk which used to be necessary in the prior arttwo-tank structure nor the complicated adjustment mechanism. The devicecan also have a higher reliability in measuring precision and can bereduced in size and complexity.

As a milk passage 7 which communicates with the tank 5 is formed on theperipheral wall of the hollow swinging member 2 which has a filling port6 projecting upward from the shaft 1 to let the milk in, the milk flowsaxially when it is being filled in the tank 5 to thereby make theswinging member 2 less susceptible to the force of the milk. Theinfluence of the milk flow in the axial direction at the time ofdischarge on the rotational movement of the swinging member 2 isminimized to attain a higher precision in measurement of rotationalcycles. This naturally leads to a higher precision in measuring of milk.

The hollow swinging member 2 in this embodiment may be circular orrectangular in cross section as shown in FIGS. 8 and 9 in order tosimplify the molding process as well as to reduce the cost. Any suitablecommercial products available in the market may be used.

As shown in FIG. 10, the outlet port 4 and the filling port 6 of thehollow swinging member 2 may be formed as an integral member byconnecting the peripheral walls of the tank 5 and the passage 7. In sucha case, the capacity of the tank 5 can be substantially increased, whichprevents foam from flowing out even if mixed in the tank 5 and floatingon the upper portion of the liquid inside the tank. This alsocontributes to the higher precision in milk measuring in terms of thetime or the rotational cycle for a predetermined milk quantity or weightto be accumulated in the tank 5.

The angle formed between the swinging member 2 and the milk passage 7 isformed in a manner to cross central axes of both members at an acuteangle as shown in FIG. 7. As the axis of the hollow member is inclinedagainst the horizontal line so that the outlet port 4 is directed upwardat the time of milk filling, the outlet port 4 of the tank 5 may beconstructed simply without providing specially for preventing the milkfrom flowing out.

In this embodiment, a projection piece 8a is provided as a stop means 8in a manner to abut against an end of the balance section 3 when theaxes of the outlet port 18 and the passage 7 become coaxial, but theshaft may be provided with a mechanism as a stop means 8. However, thestop means is preferably provided apart from the shaft 1 as thestructure, if doubling as a shaft-and-stop means, becomes complicatedand tends to fail because of the large force applied thereon.

Explanation will now be given to the first measuring method according tothis invention referring to the embodiment shown in FIGS. 2 through 6and FIGS. 13 through 15.

FIG. 13 is a graph showing a lactating curve of general lactatingcharacteristics of cows where the milk flow rate (g/sec.) is plotted onthe vertical axis and the time (sec.) on the lateral axis. The hatchedportion represents the filling cycle and the remainder the dischargingcycle. The area of the hatched portion in the graph represents theweight of the milk which accumulates in a tank for one cycle (g/cycle).One cycle is defined by one filling and discharging movements of theswinging member 2 and the time needed therefor is defined as arotational cycle T (sec/cycle) which is measured by the sensor means 9.FIG. 14 is a diagram to show the signals from the sensor means 9 and thecycle T. The diagram corresponds to the lactating curve of FIG. 13. Theweight of the milk y (g/cycle) which flows from the outlet port 18 intothe measuring chamber 22 within a rotational cycle T is detected inadvance as y - T characteristic curve. FIG. 15 shows an example of they - T characteristic curve for the device shown in FIG. 7. The partialmilk amounts y₁, y₂, . . . y_(n) from the outlet port corresponding torespective cycles T₁, T₂, . . . T_(n) which are measured by the sensormeans 9 are obtained from the y - T characteristic curve. The totalamount Y can be obtained by summing up all the partial amounts asexpressed by the equation below, ##EQU3##

According to the first measuring method, errors in measurement can beminimized.

Although the device shown in FIG. 7 is used as an example to show themethod of measuring milk weight in the first invention method, thepresent invention by no means is limited to the weight measurement butmay be extended to the volume measurement.

The second measuring method will now be described in detail referring tothe device shown in FIG. 7 and FIGS. 16 and 17.

FIG. 16 shows a lactating curve similar to FIG. 13 wherein the hatchedportion represents the filling time in the tank 5 (sec./cycle) t₁, t₂ .. . t_(n) while the letters s₁, s₂, . . . s_(n) the discharging the(sec./cycle). The area of the hatched portion W represents the weight ofmilk accumulated in the tank 5 which is always constant FIG. 17 is adiagram which shows the signals from the sensor means 9 and the fillingand the discharging times t. and s. The portion circumscribed by thelateral axis and the curve represents the total milk amount in FIG. 16.The partial milk amount at the filling time is equivalent to the weightof milk W for one cycle (g/cycle) of the tank 5 and is constant. Thepartial milk amount at the discharging time can be obtained bycalculating average partial flow rates at two points in the filling timeimmediately before and after the discharge, obtaining an arithmetic meanof the two, and then calculating an average partial flow rate from themean. The average partial flow rates q.sub. i and q_(i+1) (g/sec.) atthe filling times t_(i) and t_(i+1) is expressed as below. ##EQU4## Ifit is assumed that the average partial flow rate r_(i) at a dischargingcycle s_(i) between the two time points in the filling cycle t_(i) andt_(i+1) is expressed by the equation, ##EQU5## the total sum of the milkcan be obtained by measurement for n times as shown below. ##EQU6##

As described in the foregoing, arithmetic means are obtained from thepartial flow rates at two time points immediately before and after thedischarge in the filling cycle in this method and, therefore, comparedwith the prior art method where an average partial flow rate at only onefilling time point is used, the method can readily cope with a suddenchange in the flow rate during the milking operation to attain a higherprecision in measurement.

INDUSTRIAL APPLICABILITY OF THE INVENTION

As described in the foregoing, as the measuring device and the methodtherefor enable highly precise measurement, it is applicable to thesystems or the apparatuses which detect the end of milking operation bydetecting the decrease in the milk amount. The device is also applicableto general devices for measuring the flow rate other than in milkingmachines.

We claim:
 1. A milk amount measuring device for milking machinescomprising a measuring chamber (22) having an upper end and a lower end,a port for continuously supplying milk into the upper end of themeasuring chamber, a horizontal shaft located within the measuringchamber intermediate the upper and lower ends thereof, a swinging member(2) mounted on said shaft for rotation in the vertical direction aroundsaid shaft and including a milk tank, said swinging member beingdisplaceable rotationally about said shaft between a first position forreceiving milk in said milk tank from said port and a second positiondischarging the milk from said milk tank, said swinging member alsocomprises a balance section (3) having a weight located on one side ofsaid shaft and said milk tank (5) located on the opposite side of saidshaft, said milk tank being open at the upper portion thereof, stopmeans (8) located within said measuring chamber and located in the pathof said swinging member to define the position of said swinging memberin the first position thereof, and a sensor means (9) for detecting therotational cycles of said swinging member (2) between the first andsecond positions thereof.
 2. The milk amount measuring device formilking machines as claimed in claim 1 wherein plural blocks 30 of smallweight are mounted inside said balance section 3 in a detachable manner.3. The milk amount measuring device for milking machines as claimed inclaim 1 wherein a second stop means 8 abutting on said swinging member 2is mounted in a detachable manner with a resilient member 8b such asrubber for defining the second position thereof.
 4. The milk amountmeasuring device for milking machines as claimed in claim 1 wherein saidshaft extends through said swinging member (2) with an O-shaped ring ofa resilient material such as rubber mounted in said swinging member andencircling said shaft for supporting said shaft from said swingingmember.
 5. The milk amount measuring device for milking machines asclaimed in claim 1 wherein said swinging member 2 comprises a hollowmember which is partitioned on both sides of the shaft 1 into saidbalance section 3 comprising a weight on one side and said milk tank 5haivng an outlet port 4 on the other side, and a milk passage 7 whichprojects upwardly from the shaft 1 in the first position of saidswinging member, a filling port 6 on the upper end thereof in the firstposition of said swinging member for letting milk in, and said milkpassage communicates with said milk tank
 5. 6. The milk amount measuringdevice for milking machines as claimed in claim 5 wherein the swingingmember 2 comprising said hollow member is circular in cross section. 7.The milk amount measuring device for milking machines as claimed inclaim 5 wherein the swinging member (2) comprising said hollow member isrectangular in cross-section.
 8. The milk amount measuring device formilking machines as claimed in claim 5 or 6 wherein said milk tank 5 andsaid milk passage 7 have peripheral walls connected as an integralstructure in communication with said outlet port 4 and said filling port6.
 9. The milk amount measuring device for milking machines as claimedin claim 5 or 6 wherein said milk passage 7 and said swinging member 2each have a central axis which cross each other at an acute angle. 10.The milk amount measuring device for milking machines as claimed inclaim 5 or 6 wherein a projecting piece 8a abutting against an end ofsaid balance section 3 is formed as said stop means in a manner to makethe axes of said milk supplying port 18 and of said milk passage 7coaxial.
 11. The milk amount measuring device for milking machines asclaimed in any one of the claims 1 through 5 wherein said sensor means 9is formed by combination of a reed switch 10 and a permanent magnet 11.